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qpens
02-14-2003, 05:48 PM
There seems to be so much expertise on this board, I thought that I would ask if anyone has any ideas on how to "re-blacken" or "re-carbonate" oxidized hard rubber. In the "pen world" we call it "chocalating". The black hard rubber turns from black to brown and gets a dull finish. Buffing is not an option because most old hard rubber pens have imprints and chasing that would be removed. I wonder if there is a chemical solution that someone knows about? We've tried bleach, 409 cleanser, Super Clean, different tire products...all with limited success. Any ideas out there?
Thanks in advance.
Michael

wierdscience
02-14-2003, 10:56 PM
Sodium hydroxide better known as caustic soda dialuted with water is what I have used to restore the black finish on old tractor tires and the like.

Thrud
02-14-2003, 11:07 PM
Michael

Use a commercial tire cleaning solution and then follow up with a UV protectant. Amsoil makes a product called "Briteside" that works very well, but be warned that it can attack Aluminum and Magnesium wheels.

I also use it to remove pitch from my saw blades and router bits. Amsoil also has a UV protectant that seems to attract less dust than "Armourall" but I don't remember its name.



[This message has been edited by Thrud (edited 02-14-2003).]

Techtchr
02-15-2003, 10:12 PM
Have the same problem with musical instruments made of hard rubber, but I solve the problem by buffing them carefully. I'll be interested to see if there is a chemical dip or other method for bringing back the black finish. I've tried all the typical solvents, haven't found one that works.

Matt

NAMPeters
02-15-2003, 10:31 PM
Is't the black color from carbon black? If so then the lose of color is due to the loss of the carbon black IMHO. Then buffing removes a small amount of material to then present the carbon black. If this is the case then a means needs to be developed to reintroduce fresh carbon black to the surface. Just thinking out loud.

------------------
Neil Peters

[This message has been edited by NAMPeters (edited 02-15-2003).]

Oso
02-15-2003, 10:52 PM
Seems like a material that can be soaked in would correct that by a refractive index effect. It will bring up the black appearance.

Essentially the rubber has broken down and isn't the same material as it was. There isn't any way to put it back, really. Possibly rubbing with the latex that is used on bicycle tire sidewalls?

If it were not rubber, I would say an oil.

Have done this with other materials. But even hard rubber may be affected by petroleum oils, so you may have to find something else.

George Hodge
02-15-2003, 11:09 PM
Have you tried black shoe polish?

docsteve66
02-16-2003, 10:54 AM
Oso: What is "a refractive index effect"? How does it make things Black? My optic knowledge is minimal so may be just a lead where to start looking?
Steve

Techtchr
02-16-2003, 11:13 AM
My experience with HR instruments is that solvents, even soap and water clean the surface, and make the problem even worse, turns the HR brownish green. So far for me the only solution has been buffing, then carefully wiping off the buffing residue. Oiling the surface just seems to make it a shiny ugly color instead of a dull ugly color.
Haven't tried shoe polish. Thank gooodness synthetic materials have gotten better over the years, and the only HR instruments are antiques, and mouthpieces.

Matt

docsteve66
02-16-2003, 02:46 PM
Matt: I suspect, in your ignorance http://bbs.homeshopmachinist.net//smile.gif, that you refere to "moputh pieces" for musical instruments. Hard rubber in a good smoke pipe is a joy, and plastic do not cut it no how!!!!!!.

And pipe stems do turn green as said before, and, other than removing material (and the surfece is never the same again) I know of no way to polish the stems.

Wish I had a bucket ful of hard rubber stem pipe pipes.
Streve

Techtchr
02-16-2003, 04:16 PM
Steve, My reply was about hard rubber instruments. I am ignorant about smoking devices. I never smoked... anything...Honest. But now that you mention it Grandpa had pipes and I imagine the stems were hard rubber. Good instrument mouthpieces are still hard rubber. Instruments bodies are either wood or have progressed to different plastics such as ABS, Delrin, and polyproplyene to name a few. The only hard rubber instruments I run into now are antique Albert System clarinets.

Isn't the point of this discussion that, pen bodies, instruments, and now pipes all have the same ugly problem? Who's the Chem E in the group that can give us a solution?

Matt

docsteve66
02-17-2003, 03:49 PM
Matt: I never used tobacco until I was 28 years age. Started on pipes as part of my job. Until they put cancer warning on pipe tobacco, I ain't stopping.

anyway, Hard rubber combs are also one of the little pleasures replaced by plastics. Wonder how barbers handle the discoloration?
Funny how hard rubber feels so good for handles, mouthpieces . Didn't the old mercedes use hard rubber knobs?

SJorgensen
02-20-2003, 02:14 AM
DocSteve,
You have to be kidding about the Cancer warning. I doesn't take a rocket scientist or government warning to figure it out. If you enjoy it and accept the risk then go ahead and enjoy. And this coming from "Doc" Steve.
Spence

darryl
02-20-2003, 04:48 AM
I use a product called rubber renue to rejuvenate pinch rollers. I use it on my windshield wipers too. It seems to return the rubber to a newer state, might work for you. Get it from an electronics wholesaler, made by MG Chemicals, MG 408. Heed the warnings, it's not good for you.

docsteve66
02-20-2003, 02:18 PM
Spence: I am not kidding. Good studies show no increase in cancer among pipe smoker excepting lip cancer andthat is a rare one.

I have little use for the junk science where a person decides that some thing is bad and then hunts for evidence to so prove and disregards evidence that does not support the desired theory.

As "proof" (my version of junk science) there is no cancer warning on pipe tobacco packages. Which leads to theinteresting question- why would tobacco smoked in a pipe be less harmful than that smoked in a paper tube? Is it paper that causes the problems?

Remember- for over a thousand years heavy things fell faster than light things, the sun rotated around the earth, when I was in school- matter and energy were conserved. by thetime I finished high school, they became interchangeable.

And the real intersting thing is that those "wrong" beliefs produced USEFUL results. Eclipse were predicted, engineers used "the sum of energy (or sum of forces) must equal zero".
And the belief that the earht moves around the sun is wrong, as is the idea that the moon moves aroundthe earth. The "law" of conservation of energy was accpted only in the late 1800's. it lasted only a few years, and despite the fact that now "energy and mass are not conserved individualy" wedon't look at the possibility that some thing is not working because energy and mass are being exchanged- we hunt for friction, unbalanced mass etc.

I may sound cranky- but years ago the powers that be said coffee was badfor you (changed their minds later)- but i think I survived living with asiatics and getting not "bugs" becasue I never drank water- tea maybe, but i carrried and shared coffee, which justified boilded water with no hard feelings. Man gotta decide what HE believes is truth and acton it till he finds trust worth evidience. We volted on the laws of physics and burned peole atthe stake for disagreeing- what make you think we are any smarter today?

Too many confuse "accumulated knowledge" with intelligence or truth. Where is the evidence to support the scond hand smoke theory? I think that, if second hand smoke is reallly worse than first hand smoke, the studies would have shown that tobacco PROTECTS people- becasue those who do not smoke got cancer at the greater rate.

Read a GOOD textbook on how mediacl studies "should be conducted" and you will be astounded. The concudtors advise "use samples no larger than 50 people- preferably 25" larger samples "introduce variables that confuse the results" (those are paraphases not acutual quotes).
Rant off http://bbs.homeshopmachinist.net//smile.gif
Steve

Edit comment: read the lableon a can of motor oil, then decide: arethe risks accptable to ME? if not then lets ban oil, if yes then use it. But some day , the Green types will look at oil and say "sell only to those trainedto use it"- the oil companies will likethe idea, so will the mechanics, who will oppose? you and I ? I will casue I oppose all restrictions. Education yes. restrictions nope. So hoard you oils men http://bbs.homeshopmachinist.net//smile.gif


[This message has been edited by docsteve66 (edited 02-20-2003).]